1. Field of the Invention
The present invention relates to a structural member for electronic devices, which uses a resin composition having high tensile stress relaxation properties and excellent restoration properties after extension.
2. Description of the Related Art
A thermosetting resin has been used in a wide range of fields such as electronic materials and optical materials due to its excellent heat resistance, chemical resistance, moldability, insulation reliability, and the like. Particularly, as the thermosetting resin, an epoxy resin is widely used for various purposes. However, it is also known that the epoxy resin is generally hard and has insufficient flexibility although the above-mentioned properties are excellent. Therefore, the epoxy resin may be deformed or broken due to stress or heat stress from the outside.
As a material having more excellent flexibility, there are thermoplastic resins such as polyethylene or various rubber materials as well as a silicone resin or urethane resin. In addition, regarding the flexibility of the resin material, a low elastic modulus, high tensile extension, and high restoration properties after extension are also necessary for use in various members.
For example, the development of a flexible display such as electronic paper using such a material having excellent flexibility has progressed. In general, there are a number of types of electronic paper including an electrophoretic type and a twisting-ball type. In any of the types, the electronic paper is formed as a laminate of a display layer for implementing displaying and a conductive layer to which a voltage is applied. In the electrophoretic type flexible display, a urethane resin is mainly used (PTL 1).
On the other hand, in the twisting-ball type, a silicone is used (PTL 2).
In addition, in order to freely deform an electronic device, not only stretchability for an electronic circuit board but also resistance to deforming stress applied to mounted electronic components is necessary. Hitherto, there has been an examination in which a semiconductor element itself is provided with stretchability (PTL 3).